The invention relates generally to the fields of dentistry and orthodontics. Two-dimensional (2D) and three-dimensional (3D) digital image technology has recently been tapped as a tool to assist in dental and orthodontic treatment. Many treatment providers use some form of digital image technology to study the dentitions of patients. U.S. patent application Ser. No. 09/169,276, incorporated by reference above, describes the use of 2D and 3D image data in forming a digital model of a patient""s dentition, including models of individual dentition components. That application also describes using the digital dentition models in developing an orthodontic treatment plan for the patient, as well as in creating one or more orthodontic appliances to implement the treatment plan.
The invention provides computer-automated techniques for digitally modeling the gingival tissue of an orthodontic patient, including deformation of the gingival tissue during orthodontic treatment. These techniques are useful, for example, in creating orthodontic appliances that carry out the orthodontic treatment while fitting securely over the patient""s teeth and gums. Modeling the gums and deformation of the gums helps ensure that the orthodontic appliances do not press too tightly against the patient""s gums and cause discomfort or pain. Modeling how the gums react to treatment also provides a more complete understanding of what to expect during treatment. Moreover, computer-generated images and animations of the dentition during treatment are more complete and aesthetically pleasing when the gums are included.
The invention involves using a computer to develop a course of treatment for an orthodontic patient. In one aspect, the computer first obtains a digital model of a patient""s dentition, including a dental model representing the patient""s teeth at a set of initial positions and a gingival model representing gum tissue surrounding the teeth. The computer then derives from the digital model an expected deformation of the gum tissue as the teeth move from the initial positions to another set of positions.
In another aspect, the computer obtains a data set representing the patient""s dentition, including a digital model of the patient""s teeth at a set of initial positions and a first digital gingival model representing the gingival tissue surrounding the teeth at the set of initial positions. The computer then derives from the data set a second digital gingival model for use in modeling deformation of the gingival tissue as the teeth move. The computer, with or without human assistance, manipulates the second gingival model to model deformation of the patient""s gums.
Other embodiments and advantages are apparent from the detailed description and the claims below.